Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal ...

Thousands of solar panels glint in the sun, but the prized farmland beneath lies barren. While the Italian island of Sardinia revels in a renewable energy boom, the long arm of organised crime risks sullying its clean power ...

University of Wisconsin-Madison engineers have created a nanoscale device that can emit light as powerfully as an object 10,000 times its size. It's an advance that could have huge implications for a variety of imaging and ...

The world particle-physics community has convened in Vienna for the 2015 European Physical Society Conference on High Energy Physics (EPS-HEP2015), where the latest results in the field are being presented and discussed. ...

Automakers are looking for ways to improve their fleets' average fuel efficiency, and scientists may have a new way to help them. In a report in the journal ACS Applied Materials & Interfaces, one team reports the development ...

The 11 percent decrease in climate change-causing carbon dioxide emissions in the U.S. between 2007 and 2013 was caused by the global financial recession - not the reduced use of coal, research from the University of California ...

(Phys.org)—It was an interesting week for physics as a team of researchers with the University of California and the University of Tokyo proposed a new definition of time crystals—then proved such things don't exist—theory ...

The development of affordable and efficient ceramic fuel cells that could be used to power homes, the culmination of five years worth of work by Colorado School of Mines researchers, is featured in the July 23 issue of Science ...

EU's grid connected cumulative capacity in 2014 reached 129 GW, meeting 8% of European electricity demand, equivalent to the combined annual consumption of Belgium, the Netherlands, Greece and Ireland. According to a JRC ...

Fujitsu Laboratories today announced that it has developed technology that precisely calculates the energy required to execute various software programs running on server CPUs, for energy-efficient programming. Servers equipped ...

Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.